Don't have a skimmer. But what I CAN say is, I sure wish I had bought the more-than-twice-as-expensive PondMaster pressurized pond filter, instead of the FishMate and then the Tetra, both of which don't self-clean they way they are reputed to do. Saturday, I got a chance to see the PondMaster and how it works, and am convinced the PondMaster is better researched, designed, built, etc.
In other words, you get what you pay for.